Electrical cells, components and methods

ABSTRACT

Preferred electrode devices ( 10 ) including a substrate ( 11 ) and cathode ( 13 ) and anode material ( 12 ) coated thereon in discreet locations are described. The cathode materials desirably include multiple layers of thin metal films ( 14 ). Preferred cell devices including conductive elements and a solid state source of charged ions for migration into and through the conductive elements are also described.

REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. patent application Ser. No.60/184,962 filed Feb. 25, 2000, and of U.S. patent application Ser. No.60/267,616 filed Feb. 9, 2001, each of which is hereby incorporated byreference in its entirety.

BACKGROUND

The present invention relates generally to electrical cells, and in oneparticular aspect to electrical cells having cathodes incorporatingmultiple thin film metal layers.

As further background, electrolytic cells of various designs have beenproposed which incorporate multilayer thin films. For example, Miley etal. used flat stainless steel plates coated with multilayer thin filmsas electrodes for an electrolytic cell. Such experiments are describedin G. Miley, H. Hora, E. Batyrbekov, and R. Zich, “Electrolytic Cellwith Multilayer Thin-Film Electrodes”, Trans. Fusion Tech., Vol. 26, No.4T, Part 2, pp. 313–330 (1994). In this prior work, alternatingthin-film (100–1000 Angstrom) layers of two different materials (e.g.titanium/palladium) were employed. Others have proposed the use ofpacked-bed electrolytic cells where small plastic pellets are coatedwith several micron-thick layers of different materials. See, e.g., U.S.Pat. Nos. 4,943,355; 5,036,031; 5,318,675 and 5,372,688. Still otherelectrolytic cells have employed coated electrodes of various forms. Forexample, U.S. Pat. No. 4,414,064 entitled “Method For Preparing LowVoltage Hydrogen Cathodes” discusses a co-deposit of a first metal suchas nickel, a leachable second metal or metal oxide, such as tungsten,and a nonleachable third metal, such as bismuth.

In light of these prior efforts, there remains a need for additionalimproved and/or alternative electric cell designs which incorporatethin-film (e.g., 50–1,000-Å-thick layers) electrode configurations. Thepresent invention addresses this need.

SUMMARY OF THE INVENTION

The present invention provides, in one aspect, an electrode deviceincluding a substrate and an anode and cathode provided in discreetlocations on the substrate and thus having a gap therebetween. Thepreferred cathode includes multiple thin metal layers, desirably havingalternating layers of at least two different metals. The thin metallayers are at least partially encapsulated by a diffusion barrier layerthat is relatively impermeable to atomic hydrogen species such as ionsof hydrogen or its isotopes (e.g. protons or deuterons). Operation ofthe electrode device in the presence of an electrolyte (e.g. an aqueouselectrolyte, optionally including heavy water) filling the gap andcontacting the electrode surfaces results in the electro-migration ofthe ions (e.g. protons or deuterons) within the cathode and the creationof a region in the cathode enriched in these ions.

In another embodiment, the invention provides a method for obtaining aregion within an electrically-conductive element enriched in ions ofhydrogen or its isotopes. The inventive method includes enriching aregion of the element in the ions by electro-migration of the ions. Inpreferred modes, the element or at least a portion thereof is coatedwith a diffusion barrier that resists permeation by the ions.Additionally, the element desirably includes multiple metal layers,including for instance two or more different metals preferably arrangedin an alternating fashion. Such an element can be operated as a cathodein a so-called “wet chemistry” cell in which a liquid electrolyte isemployed, or may be operated as an element in a dry cell in which noliquid electrolyte is needed, e.g. as described in certain devicesherein.

Another embodiment of the present invention relates to a cellarrangement which comprises an electrically conductive element includinga metal in ions of hydrogen or its isotopes (e.g. protons or deuterons)are soluble, and anodic and cathodic connections to the conductiveelement. A solid-state source of the ions is provided and arranged tofeed the ions into the conductive element. For example, such asolid-state source can include a metal hydride or a correspondingdeuteride for release of hydrogen or deuterium in gaseous form, and acatalyst for splitting the gaseous hydrogen or deuterium so as toprovide protons or deuterons. The catalyst may be layered onto theconductive element, and the metal hydride may be layered onto thecatalyst. In this fashion, gas released by the metal hydride (e.g. byheating) immediately contacts the catalyst to provide protons ordeuterons, which can then migrate into and along the conductive elementwhen a voltage drop is applied across the element. Preferredarrangements include a barrier layer along at least a portion of theconductive element that resists permeation by the protons or deuterons.Cell arrangements of this embodiment may advantageously be incorporatedinto various geometric devices such as the cylindrical cell devices asdescribed further herein.

The present invention provides improved and alternative cell designs,components therefor, and uses thereof. Additional embodiments as well asfeatures and advantages of the invention will be apparent from thedescriptions herein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 provides a perspective view of a preferred electrode device ofthe invention.

FIG. 2 provides a cross-sectional view of the device of FIG. 1 takenalong line 2—2 and viewed in the direction of the arrows.

FIG. 3 provides a cross-sectional view of the device of FIG. 1 takenalong line 3—3 and viewed in the direction of the arrows.

FIG. 4 provides a perspective view of an electrolytic cell device of theinvention incorporating a plurality of electrode devices as illustratedin FIGS. 1–3.

FIG. 5 provides a cross-sectional view of a cylindrical cell device ofthe invention taken along the axis of the device.

FIG. 6 provides a cross-sectional view of a cylindrical cell device ofthe invention taken perpendicular to the axis of the device.

FIG. 7 provides a diagram illustrating an operation of the device shownin FIGS. 5–6.

FIG. 8 provides a diagram of an energy converting apparatusincorporating a device as illustrated in FIGS. 5–7.

FIGS. 9–11 show graphical data resultant from runs described in Example1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purpose of promoting an understanding of the principles of theinvention, reference will now be made to certain preferred embodimentsthereof, and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended; such alterations, further modificationsand applications of the principles of the invention as described hereinare being contemplated as would normally occur to one skilled in the artto which the invention relates.

The present invention provides electrical cells and related componentsand methods. Preferred cells will be operable using wet or drychemistries, and will desirably incorporate metal elements havingmultiple thin metal layers.

With reference now to FIGS. 1–3, shown is a preferred electrode deviceof the invention. Electrode device 10 includes a substrate 11 made of asuitable material. Since the substrate is preferably not electricallyconductive, materials such as cross-linked polymers, ceramics, or glasscan be employed, as well as suitable metals and/or metal oxides.

Substrate 11 as shown is generally planer, although substrate 11 canhave other configurations including for example convoluted or curvedconfigurations, preferably incorporating concave surfaces upon whichelectrode metals, particularly cathode metals (see e.g. FIG. 1A), arepositioned. Electrode device 10 generally includes an anode 12 and acathode 13 positioned on the substrate in discreet locations.

Anode 12 can be made of any suitable conductive material, including forexample metals such as platinum. The preferred cathode 13 includes aplurality of thin metal layers 14, for example having a thickness nogreater than about 1000 Angstroms, e.g. from about 50 to about 1000Angstroms, and a diffusion barrier layer 15. Diffusion barrier 15 isrelatively impermeable to hydrogen or its isotopes. In this regard, adiffusion barrier that has a low diffusion coefficient for hydrogen ordeuterium can be made, for instance, from chromium, silica, glass or thelike. Such a layer will retard excessive outward diffusion of ions ofhydrogen or its isotopes. This, then, enhances the ability to obtain aconcentrated or enriched region of the ions (e.g. protons or deuterons).Values above 0.5 hydrogen/deuterium atoms per host atom (palladium,nickel, etc.) are generally viewed as reflecting an advantageousenrichment, more preferably above 0.8 hydrogen/deuterium atoms per hostatom.

Barrier layer 15 covers the top and side surfaces of the metal layers 14over a portion of the metal layers 14. As shown in the illustrateddevice, barrier layer 15 covers approximately 60% to 75% of the lengthof the the metal layers 14 closest to a cathodic electrical connection16. In this fashion, a portion of the layers 14 is exposed to contact byan electrolyte, and another portion of the layers 14 closer to thecathodic connection 16 is encapsulated by the barrier layer 15.Electrode device 10 further includes an electrical connection 17 for theanode. In addition, electrode device 10 includes a gap 18 separating theanode 12 from the cathode 13, such that the anode and cathode arediscreetly located upon the substrate 11. In this and other devices ofthe invention, the cell is preferably designed and equipped such thatthe electrical current runs parallel to or along the planes of the thinfilm layers, including for example along their greatest length in thecase of rectangular films. Preferred cell designs will have the capacityto provide current densities within the thin films 14 of at least 1kA/cm², preferably providing multi-kA/cm² within the films. The highcurrent densities provided will create an electric field which enhancesthe flow of ions such as protons or deuterons, achieving higher iondensities near the negative connection to the layers.

With reference now particularly to FIGS. 2–3, layers 14 preferablyinclude layers of alternating types of metal, shown as layers 19, 20 and21. Although in the illustrated device three such layers are shown, anynumber of layers can be included, for example 2 to 20 layers or more.Preferably, layers 14 include alternating metal layers of at least twodifferent types of metal. Illustratively, layers 19 and 21 may be madefrom a metal in which hydrogen or its isotopes are relatively soluble,including for example palladium. Layer 20 can then be made of adiffering type of metal, desirably one which creates a large Fermi leveldifference between the layer 20 and the layers 19 and 21.

Suitable metals for these purposes are disclosed for example ininternational publication number WO98/07898, which is herebyincorporated herein by reference in its entirety. For purposes ofconvenience, the following text incorporates disclosure also found inthis publication.

An advantageous design of a thin-film coated electrode generallyinvolves the selection of materials with Fermi-level differences andhydrogen and deuterium absorption properties as described in G. Miley,H. Hora, E. Batyrbekov, and R. Zich, “Electrolytic Cell with MultilayerThin-Film Electrodes”, Trans. Fusion Tech., Vol. 26, No. 4T, Part 2,pages 313–320 (1994), plus consideration of the expansion properties ofthe selected materials. Since considerable compression can be toleratedbefore buckling and flaking of the thin-film layers occurs, theexpansion matching of the materials employed in the thin-film layersneed not be perfect. Thus, a fairly wide range of material choices canbe considered from among combinations of materials that might be pairedto obtain large Fermi-energy-level differences, while still offeringgood solubility and diffusivity of hydrogen and deuterium ions. Table Ibelow categorizes various materials into groups according to their FermiLevel, and is adapted from “Fermi Energy Levels (in eV),” cited in J. C.Slater, Introduction to Chemical Physics, 1st ed., McGraw-Hill, NewYork, N.Y., 44 (1939).

TABLE I Fermi Energy Level, eV for Various Groups of Metals LowIntermediate 1 Intermediate 2 Intermediate 3 High Cs 1.6 Na 3.1 Ta 5.2Pt 5.9 Fe 7.0 Rb 1.8 Ce 3.4 Ti 5.4 Pd 6.1 Cu 7.0 K 2.1 Th 3.5 Ag 5.5 Co6.2 Ni 7.4 Bi 6.3 Sr 2.5 U 3.5 Al 5.6 Pb 6.3 Be 9.0 Ba 2.3 Mg 4.5 Au 5.6Rh 6.3 Ca 3.0 Zr 4.5 W 5.8 V 6.3 Li 4.7 Mo 5.9 Ir 6.3 Cd 4.7 Zn 5.9 Os6.3 Ru 6.4

Pairing high- and low-Fermi level materials gives the maximum differencein Fermi level, for example, Cs/Be gives ΔF=7.4 eV, where ΔF representsthe difference in Fermi energy level. However, from other standpoints,such as ease of manufacture, diffusivity, and solubility, othercombinations may be desirable. Thus, alternating layers of Pd/Ni (ΔF=1.3eV), Pt/Ni (ΔF=1.5 eV), and Pd/Fe (ΔF=0.9 eV) have been used in workthus far as a compromise among these differing factors. These choicesused combinations of metals from the intermediate 3 and high groups.Other convenient choices include intermediate 3 and intermediate 1metals such as Pd/Zr and Pt/Th (ΔF=1.6 and 2.4 eV, respectively). In anyevent, it is preferred that material pairs be employed which provide aΔF of at least about 1 eV.

It should be noted that similar considerations extend to the interfacesbetween the thin-film layers, the structural substrate, and the outersurface exposed to the electrolyte or the thin film and barrier surfacecoating. Advantageous designs will thus take into account the provisionof ΔF at the outer surface, plus all internal interfaces.

In addition to ΔF considerations, the materials selected also preferablyhave the ability to allow the hydrogen or deuterium (H/D) ions enteringthe electrode or element as a result of electrolytic action to easilydiffuse through the layers, allowing large quantities of the ions to beabsorbed in all layers. Consequently, desirable material pairs offerboth reasonably high H/D diffusion coefficients (on the order of thatfor palladium or higher) and an H/D solubility also on the order of thatof palladium or higher.

In summary, optimum materials for the alternating thin-film coating canbe selected based on favorable ΔF, diffusivity, and solubilityparameters.

The diffusivity and solubility parameters for some materials which maybe used are given in Table II. Since the thin-film layers typicallyexperience an elevated temperature due to a combination of ohmic heatingassociated with the electrolysis current and heat input from reactionstaking place in the layers, the solubility should not decreasedrastically at the operational temperature. Combinations of Pd, Ni, Fe,and Ti are examples of materials that meet the desired criteria. Forexample, Ni and Ti have diffusion coefficients that are close to that ofPd, so Pd/Ni and Pd/Ti offer convenient combinations which can be usedin the invention.

TABLE II Diffusivity, D, and Solubility, C, for Various Materials MetalD(cm²sec⁻¹) C(g atom cm⁻¹) Pd 3 × 10⁻⁷  3 × 10⁻⁴ Ni 1 × 10⁻⁹  1 × 10⁻⁵Fe 6 × 10⁻⁵  4 × 10⁻⁹ Fe-Ni alloy 1 × 10⁻¹⁰ 4 × 10⁻⁶ Fe₂O₃ 1 × 10⁻¹⁸Cr₂O₃ 1 × 10⁻¹⁶

J. O'M. Bockris, M. A. Genshaw, and M. Fullenwider, Electrochim. Acta,15, 47 (1970); W. Beck, M. O'M. Bockris, M. A. Genshaw, and P. K.Subramanyan, Met. Trans., 2, 883 (1971); P. K. Subramanyan,Comprehensive Treatise of Electrochemistry, eds. J. O'M.

Other advantageous material combinations also exist. A variety ofmaterials have a higher solubility than Pd, especially at highertemperatures. Thus, from this standpoint, as well as from the view oftheir diffusivity, V, Ta, Zr, Ce, and Th are examples of additionalmaterials that are good candidates for pairing with Pd. Examples arePd/Zr, Pt/Th, and Be/Th (ΔF=1.6, 2.4, and 5.5 eV, respectively).

An additional consideration for selection of the material pairs is therequirement that minimal self-diffusion occurs, such that reasonablysharp material boundaries at the interfaces are maintained. Frequently,thin metallic films tend to diffuse into each other, such that thestability of the interface between them is compromised. Thisinterdiffusion is attributed to both of the metals in the pair havinghigh diffusion coefficients. The Ni/Pd and Ti/Pd material pairs used inwork thus far have shown minimal interdiffusion, as measured by Augerelectron scanning. This is consistent with other results reported in theliterature. Multilayered thin-film structures of Fe/Ti and Pd/Ti pairshave been studied extensively for their stability. (P. Borgesen, R. E.Wistrom, and H. H. Johnson, J. Mater. Res., 4, 821 {1989].) Experimentsinvolved the study of interdiffusion of such films as a result ofirradiation and hydrogen loading. Fe/Ti and Pd/Ti pairs were found to berelatively stable, compared to a variety of other combinations.

In summary, once material pairs are selected on the basis of ΔF,diffusivity, and solubility, then minimization of interdiffusion betweenthe pairs can also be considered. If diffusion coefficient data are notavailable, conventional Auger electron microscopy of sample structurescan be performed to measure metal profiles near interfaces to insurethat substantial interdiffusion does not exist.

Based on the foregoing reasoning, plus the need for easy fabrication,work to date has generally employed alternating layers of Pd/Ni (ΔF=1.3eV) or Pd/Ti (ΔF=0.7 eV). Combinations such as Pd/Zr, Pt/Th, and Be/Th(ΔF=1.6, 2.4, and 5.5 eV, respectively) are other attractivecombinations.

In devices such as device 10 and other devices of the present invention,the cathode including the thin films 14 may be provided on a curvedsurface such as a concave surface, or may be provided in a segmentedfashion as disclosed in WO WO98/07898 to effectively provide expansionjoints to retard any deterioration of the films.

With reference now to FIG. 4, if desired, a plurality of electrodedevices 10 may be incorporated into an electrolytic cell. For example,shown in FIG. 4 is such an electrolytic cell 30 incorporating aplurality of electrode devices 10. Cell 30 includes a plurality ofelectrode devices 10 suitably mounted therein inside a durable,non-conductive housing 31. In applications including the recovery and/orconversion of heat, cell 30 may also include a plurality ofthermoelectric converter elements 32. The thermoelectric elements 32 andthe devices 10 can be bonded to one another in a back-to-back fashion orotherwise thermally coupled in a fashion facilitating heat transfer fromthe devices 10 to the elements 32. For instance, in one embodiment, thethermoelectric element may serve as the substrate for the anode andcathode materials. These combined structures and then arranged in thecell 30 leaving spaces 33 for electrolyte flow and spaces 34 for coolantflow through the cell 30. Spaces 33 for electrolyte flow occur on theelectrode sides of the combined electrode/thermoelectric structures,providing the electrolyte for the operation of the devices 10. Spaces 34for coolant occur on the thermoelectric element side of the combinedstructures. In this fashion, as the cell is operated, a temperaturedifferential can be created across the thermoelectric converter elements32, thus promoting the generation of electric energy.

With reference now to FIGS. 5–7, shown is another embodiment of theinvention. Shown is an electric cell 40 in which structures are arrangedin a cylindrical fashion. Preferably, such a cylinder has a circularcross-section, although other cross-sections such as elliptical,rectangular, square, triangular, or irregular cross-sections arepossible. Cell 40 includes a cylindrical support member 41, preferablyalso having heat exchange structures external thereof for dissipatingheat, for example including fins 42. Support 41 defines an internalspace 43, containing other elements of the cell. In particular, athermoelectric converter element 44 is thermally connected to support41. In this regard, the thermoelectric element and other elementsdescribed herein internal of the support 41 are preferably constructedin a shape corresponding to the interior wall of the support member 41.Adjacent the thermoelectric converter, provided is a diffusion barrierlayer 45 which is relatively impermeable to hydrogen or its isotopes, asdescribed elsewhere herein. Inside of barrier 45 are located thin metalfilms 46, having features such as described above in connection withdevices 10. Extending over a portion of the length of the films 46 is acatalyst layer 47. Catalyst layer 47 contains a catalyst for convertinggaseous hydrogen or isotopes thereof into corresponding ionic forms suchas protons or deuterons. Catalyst layer 47 can include, for example,platinum black, which is well known for these purposes. A metal hydridelayer 48 is provided within the catalyst layer. A diffusion barrierlayer 49 is provided separating a portion of the hydride layer 48 fromthe thin film layers 46. Barrier layer 49 and catalyst layer 47 arearranged along the hydride layer 48 such that catalyst layer 47separates thin film layer 46 from hydride layer 48 along a portion, andbarrier layer 49 adjoins the catalyst layer and separates the hydridelayer 48 from the thin film layer 46 along a further length thereof. Atthe opposite end of barrier layer 49, there is provided a gap 50 inwhich the thin film layers 46 are not separated from the hydride layerby a barrier layer, allowing for diffusion of ions of hydrogen or itsisotopes from the thin metal layers 46 into the hydride layer 48.Provided also is an oxide layer 51 which is semi-transparent to hydrogenor its isotopes. Used in this context, semi-transparent is intended tomean that the layer 51 will admit gaseous hydrogen or its isotopesreadily into the hydride layer 48, but will resist flow of gaseoushydrogen or its isotopes in the opposite direction.

The metal hydride layer 48 can be loaded, for example, by heating thelayer 48 in the presence of gaseous hydrogen or its isotopes. This willpromote the uptake of hydrogen or its isotopes into the metal hydridelayer 48, creating a solid-state source of hydrogen or its isotopes.Further, cell device 40 may be constructed as a closed container, andcan remain pressurized with gaseous hydrogen or its isotopes prior toand during use, to maintain an equilibrium concentration of hydrogen oran isotope thereof relative to the hydride layer 48, further minimizingany “backflow” of hydrogen or its isotopes out of thehydride-semi-transparent layer region.

With reference in particular to FIG. 7, in an illustrative the operationof the cell 40, electrical current is passed through the metal films 46via anodic and cathodic attachments located and the ends of the films.This results in heating the films 46, which transfers heat to the metalhydride layer 48. Hydrogen is released from hydride layer 48, passesinto catalyst layer 47, and is converted to protons. The electric fieldwithin the metal films 46 causes an electro-migration of the protonstoward the anode. At the same time, barrier layer 49 prevents theprotons from re-entering the hydride layer within the length of themetal films 46 covered with barrier layer 49. A highly concentrated areaof proton flow will thus be created in the regions of the metal filmstructure 46 adjoining the barrier layer 49. Protons will ultimatelytraverse beyond the barrier layer 49, and can re-enter the hydride layer48 through the gap 50 located adjacent the anode. During this operation,gaseous hydrogen within the cell 40 can diffuse into the hydride layer48 to replenish the hydrogen source.

With reference now to FIG. 8, illustrated is the operation of cell 40 inan energy conversion apparatus including the cell 40 and an externalbattery 100. During a start-up phase, the external battery 100 is usedas a power source to drive a current through the metal film structure 46of the cell 40 and, if desired, to also heat the hydride layer through aseparate resistive heater element. When sufficient electricity isprovided by the thermoelectric converter element 44, such electricitycan be used to drive current through the thin film structure 46, thestart-up battery can be disconnected, and the cell 40 can then beallowed to operate in a self-sufficient manner.

It will be understood that in the operation of the cell 40 in a mannerincluding the conversion of heat energy to electricity, a heat sink willbe provided to the external surfaces of the cell 40. This may includefor example a flowing fluid such as a gas or a liquid to dissipate heatand thereby facilitate the generation of a thermal gradient across thethermoelectric element 44. As to the use of metal hydrides as a hydrogensource in the invention, two basic properties that make metal hydridesattractive are their high and reversible storage capacity per mole ofcompound, and the high energy stored per unit volume. The mass ofhydrogen that can be stored by unit volume of hydride is almost twicewhat can be stored in liquid form and thrice than as a highly compressedgas. Hydrogen is also much more stable as a hydride since as a liquid itrequires cryogenic storage tanks and as a gas it requires high-pressuretanks (˜5000 psi). One drawback is the low hydrogen weight percent,which in most hydrides ranges about 2%. Nevertheless, the energy storedin a liter of hydride may range around 1 MJ. Companies are developingnew hydrides that can achieve up to 7% weight in hydrogen content, forexample Energy Conversion Devices of Troy, Mich. has materials in thisarea.

Illustrative candidates for high density hydrogen storage includeLaNiH_(x) and FeTiH_(x). Additional candidates with their properties areshown in Table III below.

TABLE III Storage Properties of Various Hydride Materials* H₂ VolumeDensity Energy Density Material [g/dm³] [MJ/kg⁻¹] [MJ/dm³] MgH₂ 101  9.914 FeTiH_(1.95) 96 2.5 13.5 LaNi₅H_(6.7) 89 2 12.7 *Taken from MaterialScience and Technology. Vol. 3B. Part II. Cahn, Haansen and Kramer.Weinhein. New York, 1994.

Many other hydrides are known and their selection and use in the presentinvention will be well within the purview of those working in this area.

For certain applications of the invention, it will not be necessary toconsider the recharging properties of the hydride materials. It shouldbe noted, however, that most of the hydrides can be generally berecharged with times that range from seconds to hours depending of theparticular system and conditions. Some hydrides are also very tough, forexample AB₂ compounds used by Daimler-Benz allow up to 3900 charge anddischarge cycles with charging up to 80% in 10 minutes. The Ovonicdivision of Energy Conversion Devices, Troy, Mich., also has aproprietary alloy based magnesium hydride which can undergo 650 chargeand discharge cycles with negligible degradation.

Concerning the catalyst layer, platinum black (Pt-black) is a fineplatinum metal powder with particle size typically in the range of0.1–0.5 μm. Due to its fine structure, Pt-black powder possess a blackcolor, owing to large light absorption by free electrons. Pt-black canbe obtained by the different known techniques, including anelectrochemical process. This involves a method where different Pt-saltwater solutions are utilized (typically chlorides) at determined pHconditions. The Pt-black powder produced by the electrochemicaltechnique can easily be deposited on a cathode surface directly from theelectrolyte by electrolysis at low current densities. The thickness ofthe Pt-black layer on the cathode surface can be controlled by varyingthe electrolysis current density and duration.

Pt-black powder is a highly efficient catalyst for molecular hydrogendissociation to atomic hydrogen [10-11], i.e. causing the reaction(H₂→H+H). The yield of atomic hydrogen in the dissociation reactiondepends on temperature and at T˜600 K is close to 100%. Moreover, Ptblack cannot be loaded with hydrogen because the Pt metal has very lowaffinity to hydrogen. Due to the gross value of specific surface ofPt-black (S˜10–100 m²/g), a thin layer of this powder (about 0.1 micronthick) will be sufficient to totally dissociate hydrogen moleculesentering the layer due to a hydrogen gas pressure in the 1 to 10atmosphere pressure range; therefore this process appears well suitedfor loading of the multiple layer thin film (MLTF) system with pureatomic hydrogen.

Those properties of Pt-black make it possible to utilize a Pt-blackcoating in the hydrogen loaded MTLF system as an ideal H₂ to atomichydrogen converter (without losses of atomic hydrogen H in it). Thisprovides an opportunity to carry out the “dry” electrolysis process withMLTF cathode when DC/AC voltage is applied to it, as described for thecell 40 above.

As discussed above, in order to decrease the hydrogen losses and inMeH_(x), hydride/MLTF system, it is preferable to use a semi-transparent(in reference to hydrogen) oxide film (layer 51, FIGS. 5–6) which iscoated on the free surface of hydride layer. As shown in Refs. [9–10]different oxide coatings such as Al₂O₃, SiO₂, PdO, MnO₂ may be utilizedas semi-transparent barriers in reference to hydrogen loaded intometals. The principal of creating of semi-transparent transition at themetal surface having high affinity to hydrogen (MeHx) requiresutilization of a large difference of Fermi levels in oxide and metal.The thin layers of oxides presented above (about 200–500 Anstroms thick)are transparent with reference to hydrogen atoms/molecules in theprocess of their absorption from the gas phase or upon the liquid phaseelectrolysis already at room temperature. These layers are not loadedwith hydrogen by themselves, but operate as a direct transition ofhydrogen atoms to metal, where the loading occurs. When the loading ofthe metal is complete, at the interface between the metal and oxidelayer, a Double Electric Layer (DEL) is built up. As a result,positively charged protons (in loaded metals such as Pd, Ti, Mg) cannotpenetrate through the DEL at the metal/oxide interface to “vacuum” (or,for instance, return into gas phase) because they will be retarded bythe DEL. In the case under consideration, the meta-oxide interface, inreference to protons, is operated as metal-dielectric transition inreference to electrons in semiconductor diode. Thus, due to a strongdifference between oxide and metal Fermi levels, the hydrogen becomestrapped inside the metal.

The oxide layers can be deposited on the metal surface by sputtering orany other suitable techniques.

In order to produce a low weight heat sink and fins, it will bepreferred instead of Al to use modern semiconducting polymer materialsknown as doped poly-acetylene (PA) [12]. The advantage of this materialcompared to the usual metals is that it has density of only 1.0 g/cm3,that is 2.7 time less than the specific weight of Al. Moreover, PAmaterials are polymers with a high degree of conjugated bonds doped withalkaline metals, and possess high thermo and electric conductivitiesthat are comparable to metals. PA materials may also easy operate athigh temperatures (more than 800° C.).

In addition to optimization of materials, recent work at NEC Corporationto develop high efficiency cooling for advanced computers has shown thatan aerodynamic design of the fin structure can significantly increaseheat transfer rates [5]. Such a design can be adapted to the cell finconfiguration in the present invention. In addition to incorporating anaerodynamic cross-section, the lengths of the fins are progressivelyincreased downstream from the flow entrance.

Devices of the invention can be used for example in the electrolysis ofelectrolytes such as water, forming hydrogen and oxygen gases, and mayalso be used in energy conversion devices or cells which include thegeneration of heat and optionally conversion of the heat to electricalenergy, and/or in causing transmutation reactions. Devices of theinvention may also be used to provide densified regions of ions orhydrogen or its isotopes, increasing the probability of and facilitatingthe further study of ion-ion reactions or ion-metal reactions, includingexploring fusion and related reactions.

For the purpose of promoting a further understanding of the presentinvention and its principles and advantages, the following specificExamples are provided. It will be understood that these Examples areillustrative, and not limiting, of the invention.

EXAMPLES

1. Plate-Type Electrodes Including Cathode and Anode

Research has demonstrated that proton-metal reactions can be created byloading multi-layer thin films (MTLFs) with protons to achieve a loadingratio of approximately 0.9 protons per atom of palladium (Palladium istypically a basic constituent of the MLTF which is composed of alternatelayers of metals such as nickel and palladium of thickness roughly500–1000 A per layer). The exact mechanism driving the proton reactionis still under study, but the present view is that once this loading isachieved, a coherent structure, termed the gamma phase [1], is createdthat incorporates the protons and the lattice atoms. These coherentstructures in turn permit tunneling-type reactions and provide a latticerecoil mechanism to absorb the energy released, resulted in heating ofthe MLTF. Experimental studies described herein using the MLTFconfiguration and loading methods disclosed herein have demonstratedthis mechanism, achieving specific powers in excess of 500 W per gram ofMLTF. Reactions can be achieved over extended periods providing the highproton loading and non-equilibrium ion/electron flow conditions can bemaintained.

For these experiments, an electrode device was constructed generally asdescribed in connection with FIGS. 1–3 above. In this design, the MLTFsection was sputtered on the lower section of the substrate and servedas the cathode. The cathode included a total of 5 thin film layers,prepared as alternating layers of palladium and nickel. Palladium servedas the first and last metal layers of the cathode (not counting thechromium barrier layer). The anode, typically platinum, was placed onthe top of the substrate plate with a gap between the two. An objectiveof this design is to cause the electrical flow (from anode to cathodevia electrolyte that fills the gap) to flow parallel to the MLTFsurface. This creates a high current density and maximizes the voltagedrop (giving a maximum electrical field) in the films due to their smallcross section perpendicular to the current flow direction. The electricfield. in the MLTF serves to drive protons that enter the film towardsthe lower end (towards the cathode electrical connector). This flowcauses the proton concentration in the MLTF to maximize at the lower endof the cathode, maximizing reactions and reaction potentials in thatregion. To insure a high loading occurs in this region, the lowertwo-thirds of the cathode surface (electrolyte interface side) wascoated with a thin (<100 A) barrier layer formed of chromium to reducediffusion of the protons out of the film. In summary, these twofeatures, a high hydrogen loading (approaching 0.9 atoms hydrogen peratom MLTF metal), and a high current density (approaching 1 kA/cm²) areadvantageous features of this electrode. This then makes a high reactionrate possible, giving heat source rates over 500 W/g of MLTF metal.

The electrode device was inserted in a small, well-insulated Dewar alongwith appropriate temperature sensors to perform calorimetry.Considerable effort and development was expended on the film depositiontechnique to achieve good bonding, i.e. provide a reasonable lifetimedespite the severe conditions of loading and heating encountered duringoperation. These techniques are described in [14]. These preliminarycells were purposefully designed to operate at relatively low powers andtemperatures (few 100 mW and <30° C.) to simplify operation. 12 runshave been carried out with various thin-film coatings. Further detailsabout the operating conditions, calibration, and data analysis arepresented in [14]. A plot of the excess power measured during a typicalrun is shown in FIG. 9 and the excess power results for all 12 runs aresummarized in Table IV.

TABLE IV Summary of Initial Runs Input Power Excess Power PercentageCell mW MW Excess Power 1 440 308 70 1 210 189 90 1 115 103 90 1A 139122 88 1A 758 500 66 1A 101  19 19 2 192  23 12 2 104  46 45 3 102 102100  3  75  30 40 3 101  97 97 3 215 174 81

As seen from Table IV, all the these cells consistently produced excesspower, defined as the additional power obtained from the cell above theinput joule heating (the variation is largely due to changes in filmdesign which was part of this initial study). The estimated uncertaintyin the excess power levels is about 20 mW, such that the resultsreported are quite definitive despite the relatively low absolute powerlevels. While the absolute excess powers densities are low in absolutevalue, when computed on the basis of power per unit volume of metalfilm, they are comparable with the earlier bead experiments. The pointis that with this electrode configuration, only a small fraction of thecell volume contains active metal. When considered on this basis, theseelectrodes provide forefront results. For example, these electrodesprovide excess powers of ˜10–20 W/gram of metal (Pd, Ni, etc) incomparison to only 0.1–0.4 W/g reported by Miles a solid Pd electrode,or ˜0.006 W/g reported recently from experiments at Stanford ResearchInstitute using the “L. Case Catalyst” technique (Pd coated commercialcatalysis particles) [15]. Thus, the present electrode cells offer anexcess power density (per gram of metal) that is one or two orders ofmagnitude higher than that reported from other related experiments.

Such electrode devices can be scaled up to higher power cellsincorporation of multiple electrodes into the electrolytic cellcontainer in order to increase the “packing fraction” of film material(volume of MLTF vs. volume of substrate and electrolyte). With thepresent compact electrode design which has both the anode and cathodeplated on a single glass plate, insertion of multiple electrodes in thecalorimeter for testing purposes is also readily achievable. Consider,for example, a cell of the same volume, but with 100 glass plates thathave electrodes sputtered on both sides (vs. present single-sidedplates). Behavior of the electrodes the same as for the single electrodeexperiments reported here would produce about 38 W excess power withabout 40 W input. In addition, if the MLTF layer design is upgraded tothat employed in earlier thin-film bead experiments [12], which providehigher excess heat percentages, excess power gains approaching 500%could be obtained. Then, the excess power in the preceding example wouldapproach 190 W. Such a unit provides the basis for an attractivepractical battery-type unit. Then scale-up to a multi-kW unit fordistributed power cells would follow the same lines, adding yet moreelectrodes. A key added technology would involve incorporation of aheat-electrical conversion system. Assuming higher temperature operationis achieved, the present electrode design lends itself nicely to use ofan integrated electrode and energy converter.

A possible integrated cell arrangement is illustrated in FIG. 4,discussed above [see 14, 16, 17]. In one such embodiment, a solid-stateheat-electrical converter such as thermoelectric material or a “quantumwell” layer is directly sputtered on the electrode on the side notbonded to the thin-films. Channels between these plates alternate withcoolant and electrolyte, electricity being extract directly from thethermoelectric or quantum well layers. Such an arrangement would providethe desired compactness while offering a simple arrangement for handlingelectrode maintenance. Since the thin-film electrodes could bemass-produced using semi-conductor-manufacturing techniques, a costeffective power cell can be envisioned.

In further support of the plate type electrode studies, a basic hydrogenisotope loading experiment was carried out using a 50-mm diameter Pdwire, 1-m long, as the cathode [14]. This configuration provideselectrical loading properties similar to the thin-film, but allows foreasier diagnostics of the loading process itself. The configuration isrelated to other wire loading experiments by Celani, et al. [18], inwhich compatible results were observed. Thus it provides importantsupporting physics data. This wire was pre-conditioned and annealed toprovide an oriented crystalline structure. The change in resistance ofthe wire was measured continuously during the loading process in orderto determine the loading ratio (atoms H or D/atom Pd). At a loading ofabout 0.85, the resistance suddenly dropped to values well below thewire's initial value, as shown in FIG. 10. This rapid change isattributed to a phase change into the gamma phase of the D-Pd system. Asseen from FIG. 11, the phase change was quickly followed by a shortburst of high power output (order of kW) which rapidly heated theelectrode, causing another phase change whereby the resistance returnedto a value above the original. At that point, an excess power of ˜1 Wattwas obtained for about one hour before damage to the cell wiring forcedshutdown of the run.

2. Hydride Storage Pressure Loading MLTF Cell Design

Electrolytic loading is attractive since it is well known that theelectrolytic approach can produce very high loading ratio due to theeffect of the double layer electrical potential that develops at theelectrode. surface.. Indeed electrolytic loading of metals likepalladium can obtain high values like 0.8 protons/atom, in contrast toother techniques such as high-pressure gas loading which is generallylimited to less than 0.5 protons/atom. The reason this is possible withelectrolytic techniques revolves around the fact that surface potentialsprovide a mechanism to ionize and then drive hydrogen into the metal inionic form. Several prior studies of pressure loading, to obtain highproton/metal ratios in Pd electrodes have been reported by U.Maatermatero [2], and by X. Li [3]. Both of these studies are verypositive in that excess heat production was achieved by the differenttechniques employed by these two researchers.

The present invention provides cells designs which employ loading ionichydrogen from a hydride storage layer. In particular, as generallyillustrated in FIGS. 5–7, the MLTF is coated on top of a hydride with anintermediate, platinum-black layer, and a small electric field isapplied externally. Hydrogen released from the hydride by heating isionized in the platinum-black layer and enters the MLTF. The electricfield is set up to assist inward transport of the protons and also drivethem along the MLTF layers. As seen from FIGS. 5–7, a barrier layer isplaced in the center region between the hydride and the MLTF. Protonsflow along the films behind the barrier layer so they do not reenter thehydride until they arrive at the opposite end of the film. Thus thisdesign creates an electro-migration assisted technique to achieve anultra-high proton loading and simultaneously provides a proton flow inthe films. Flow is believed to be an advantageous component infacilitating the reactions. These flows are illustrated schematically inFIG. 7. In addition to the MLTF-hydride component, as shown in FIGS.5–7, in the overall power cell using pressure loading, a thermo-electricconverter and heat sink are provided as discussed in the generalDescription above. The center of the cylindrical cell is open to providea large volume for initial loading of the hydrogen gas into the hydride.The gas is admitted into the cell at about 1 atmosphere while thehydride is resistively heated to several hundred degrees using anexternal battery. A barrier layer on the inner surface of the hydrideadmits gas flow into the hydride but retards flow in the oppositedirection. Once the hydride is loaded, the hydrogen gas tank is removedand the cell valved off. The heater battery is also removed. In thiscondition the cell can be stored for extended periods of time withoutproducing power. When operation is desired, the heating battery isreconnected and the hydrogen is driven out of the hydride at atemperature exceeding 350 degrees F. A battery is also connected toprovide the bias field along the MLTF. Once the proton flow and loadingare created, proton-metal reactions in the MLTF provide a vigorousheating source. At this point the external batteries are disconnectedand the power cell is fully operational and portable.

The thermal-electric converter and heat sink are important components ofthis system when the production of electrical power is desired, whichdetermine its overall efficiency and also may contribute a majorfraction of the overall weight. It is possible to use a conventionalthermo-electric converter, which operates with 4.5% efficiency with a200-degree delta-T. It is expected however to be advantageous to employan advanced quantum well type thermo-electric element, which couldoperate at 20% efficiency under similar conditions. Heat sink technologycould use a small fan of the type employed in personal computers for aircooling. Aerodynamic fin designs can also be used.

REFERENCES

The following references and all other references cited in this documentare indicative of the skills possessed by those practicing in the artand are hereby incorporated by reference their entirety as if eachreference had been individually incorporated by reference and fully setforth.

-   [1] G. Preparata,” QED Coherence in Matter”, World Scientific    Publishing Co., 1995-   [2] U. Mastromatteo, “Hydrogen Loaded Thin Nickle Layers Show High    Temperature Hot Spots”, Proceedings Asti Workshop on Anomalies in    Hydrogen/Deuterium Loaded Metals, Rocca d'Arazzo, 27–30 Nov.    1997, p. 63.-   [3] X. Z. Li, S. X. Zheng, H. F. Huang, G. S. Huang, W. Z. Yu, “New    Measurements of Excess Heat in a Gas Loaded D-PD System”,    Proceedings ICCF7, p. 197.-   [4] Hi-Z technology, Inc., San Diego, Calif.-   [5] Staff writers, “Cooling Solution: A surprise heat sink design    prepares a computer manufacturer for the next wave of hotter, faster    CPUs”, Mechanical Engineering, p. 78 July 2000.-   [6] Hartley, F. R., “The chemistry of platinum and palladium, with    particular reference to complexes of the elements”. New York, Wiley.    1973.-   [7] Thorne, L. R, “Platinum catalytic igniters for lean hydrogen—air    mixtures”, Nuclear Regulatory Research, Washington D.C., 1988.-   [8] Y. Fukai: The Metal Hydrogen Systems: Springer Series in    Material Science #21. Berlin, Springer (1993).-   [9] E. Yamaguchi and T. Nishioka: Japan J. Appl. Phys., 26, L666    (1990).-   [10] A. G. Lipson, A. S. Roussetski, B. F. Lyakhov et al: Fusion    Tech, 38, 155 (2000).-   [11] O. Joshiro, K. Naokara and J. Murata: J. Polymer Sci Polymer    Phys., 24, 2059, (1986).-   [12] Miley, G. H., “Possible Evidence of Anomalous Energy Effects in    H/D-Loaded Solids Low Energy Nuclear Reactions (LENRS), Journal of    New Energy, 2, no. 3–4, pp. 6–13.-   [13] Miley, G. H. “Characteristics of Reaction Product Patterns in    Thin Metallic Films Experiments,” Proceedings, Asti Workshop on    Anomalies in Hydrogen/Deuterium Loaded Metals, Asti, Italy, Nov.    27–30, 1997.-   [14] George H. Miley, et al., “Experimental Status and Potential    Applications of a Thin-Film Low Energy Nuclear Reaction (LENR) Power    Cell”, ICONE-8, April 2000-   [15] McKubre, M. “Recent Loading and Excess Heat Experiments at    SRI,” Proc., ASTI Workshop on Anomalies in H/Loaded Metals, Nov.    27–30, Asti, Italy, Societa Italiana di Fisica, Bologna, Italy,    1999.-   [16] Miley, G. H., “Emerging Physics For a Breakthrough Thin-Film    Electrolytic Cell Power Unit”, AIP Conference Proceedings 458, pp.    1227–1231, Space Technology & Applications International Forum,    University of New Mexico, Albuquerque, N.Mex., Jan. 31 to Feb. 4,    (1999)-   [17] George H. Miley and Eric Rice, “Low Energy Reaction Cell for    Advanced Space Power Applications” Proceedings Space Technology &    Applications International Forum, University of New Mexico,    Albuquerque, N.Mex., Feb. 11 to Feb. 15, (2001).-   [18] F. Celani, et al., “A Preliminary D/Pd Loading Study: Anomalous    Resistivity Transition Effect,” Proc., Asti Workshop on Anomalies in    H/D Loaded Metals, ASTI '97, Societa Italiana di Fisica, Bologna,    Italy, 1999, pp 7–16.

1. A device suitable for energy conversion, comprising: at least oneelectrode device, said electrode device comprising; a substrate; a firstelectrode on the substrate, said first electrode comprising multiplemetal layers including at least one layer of a first metal and at leastone layer of a second metal; and a second electrode on the substrate ina location discrete from said first electrode; and at least onethermoelectric converter element.
 2. The device of claim 1, wherein saidlayers each have a thickness in the range of about 50 to about 1000Angstroms.
 3. The device of claim 1, wherein said first metal and saidsecond metal have a Fermi level difference of at least about 0.5.
 4. Thedevice of claim 1, wherein said first electrode further includes abarrier layer, and wherein at least a portion of said multiple layersare positioned between said barrier layer and said substrate.
 5. Thedevice of claim 1, wherein said first metal is palladium.
 6. The deviceof claim 5, wherein the layer of palladium has a thickness in the rangeof about 50 to about 1000 Angstroms.
 7. The device of claim 6, whereinsaid first electrode has at least 5 metal layers, said metal layersincluding at least two layers of palladium.
 8. The device of claim 1,wherein said substrate is substantially planar.
 9. The device of claim1, wherein said substrate comprises a concave surface, and wherein saidfirst electrode is positioned upon said concave surface.
 10. The deviceof claim 1, wherein said substrate is non-conductive.
 11. The device ofclaim 10, wherein said substrate comprises glass or ceramic.
 12. Thedevice of claim 1, wherein said metal layers are formed by sputteringand/or plasma deposition.
 13. The device of claim 12, wherein said firstmetal and said second metal have a Fermi level difference of at leastabout 0.5.
 14. The device of claim 13, wherein said first metal ispalladium.
 15. The device of claim 1, comprising a plurality of saidelectrode devices.
 16. The device of claim 15, comprising a plurality ofthermoelectric converter elements.
 17. The device of claim 15, whereinsaid electrode devices are substantially planar.
 18. The device of claim17, also comprising a plurality of thermoelectric converter elements,said electrode devices and thermoelectric converter elements arranged inan alternating fashion.
 19. A device suitable for energy conversion,comprising: at least one cell device comprising: a source of ions ofhydrogen or an isotope thereof; an electrically conductive elementincluding a metal in which said ions are soluble; and said cell deviceconfigured to cause electro-migration of said ions so as to form aregion within said conductive element enriched with said ions; and atleast one thermoelectric converter element.
 20. The device of claim 19,wherein said conductive element comprises multiple metal layers.
 21. Thedevice of claim 20, wherein said multiple metal layers include at leastone layer of a first metal and at least one layer of a second metal. 22.The device of claim 21, wherein said first metal is palladium.
 23. Thedevice of claim 19, also comprising a barrier layer configured topromote formation of said enriched region of said conductive element.24. The device of claim 19, wherein said source of ions comprises aliquid electrolyte.
 25. The device of claim 24, wherein said conductiveelement comprises at least one layer of a first metal adjacent to atleast one layer of a second metal.
 26. The device of claim 19, whereinsaid source is a solid source.
 27. The device of claim 26, wherein saidconductive element includes multiple metal layers.
 28. The device ofclaim 27, wherein said multiple layers include a layer of a first metaladjacent to a layer of a second metal.
 29. The device of claim 28,wherein said first metal and said second metal have a Fermi leveldifference of at least about 0.5.
 30. The device of claim 26, whereinsaid solid source comprises a metal hydride.
 31. The device of claim 30,also comprising a catalyst for converting gaseous hydrogen or an isotopethereof to a corresponding ionic hydrogen or an isotope thereof.
 32. Thedevice of claim 31, wherein said catalyst comprises platinum black. 33.The device of claim 30, also comprising an amount of gas of hydrogen oran isotope thereof in communication with said metal hydride.
 34. A celldevice comprising: a solid source of ions of hydrogen or an isotopethereof, said solid source formed as a layer having a generallycylindrical shape; a conductive element in which said ions are soluble,said conductive element formed as a layer having a generally cylindricalshape; a closed container that is generally cylindrical in shape, theclosed container having an interior, with said solid source and saidconductive element located in said interior, and said solid source andsaid conductive element corresponding in shape to an internal surface ofsaid container; an anodic connection to said conductive element at afirst location; a cathodic connection to said conductive element at asecond location; a barrier layer located between said anodic connectionand said cathodic connection; said solid source arranged to provide saidions into said conductive element upon the application of currentthrough said conductive element; said solid source effective to exchangesaid ions to and from said conductive element on either side of saidbarrier layer, but not through said barrier layer; and a thermoelectricconverter element in heat-exchange relationship with said conductiveelement and with said container.
 35. The device of claim 34, alsocomprising heat transfer elements external of said container.
 36. Thedevice of claim 34, wherein said conductive element comprises multiplemetal layers.
 37. The device of claim 36, wherein said multiple metallayers include at least one layer of a first metal and at least onelayer of a second metal.
 38. The device of claim 36, wherein said layerseach have a thickness in the range of about 50 to about 1000 Angstroms.